On the 8th of December 2011, Uniten was fortunate enough to be graced by the presence of Prof Michihiro Furusaka,Phd. He is a professor at the Graduate School of Engineering at Hokkaido University, Japan, working in the field of neutron instrumentation and optics. Currently, he is developing a new mini-focusing small angle neutron scattering (mfSANS) instrument.

He came to Uniten to conduct a lecture on quantum beam technology and its application in various fields including nuclear engineering.This was all made posible by Nuclear Malaysia.

In many applications such as fuel cells, batteries and superconductors, most of the key properties are linked to the nanostructure of their constituent materials. Any attempt at the tuning of this nanostructure in order to optimize the application properties, however, requires the ability to extract the morphological details on length scales ranging from the sub-nm scale up to the micron scale. Moreover, since the application properties are defined by the average of the bulk material, the statistically representative characterization of the average nanostructure is a necessity.

Small-angle scattering (of light, X-rays, and neutrons) is a unique nanostructural characterization technique capable of obtaining exactly this; providing average morphological parameters over volumes ranging from cubic micrometers to cubic centimeters. The widespread adoption of this technique, however, has been hindered by a complicated data interpretation as well as instrumental limitations.

He started of the lecture by giving a brief overview of the current situation in large neutron facilities. He also said that Small Angle Neutron Scattering instrument (SANS) are huge and expensive.Mantaining a Neutron facility is expensive and not always available in developing countries. The instruments also requires lot of manpower and budget to mantain.

SANS machine

Research activities using neutron scattering techniques are strongly hampered by its limited machine-time availability. We need very large facilities, either a research reactor or an accelerator driven neutron source, and the number of such facilities all over the world is rather limited. Also true is the number of instruments at such facilities. As a result, getting machine time of one of such instruments is also severely limited; often they are oversubscribed by a factor of three or more.

In case of X-ray, there are a lot of laboratory based X-ray instruments all over the place. Instruments are commercially available; researchers can test their ideas or new samples without writing a proposal; many researchers know how to analyze data. If you need a more powerful instrument, synchrotron radiation facilities are there.

One way of overcoming this situation around neutron scattering technique, especially for SANS instrument, would be to develop a compact unit instrument that can be installed many on a beamline. The unit should be of low cost and can also be installed at low power accelerator based neutron sources. The answer to this is the mfSANS instrument. By using a neutron-focusing technique, like an ellipsoidal mirror developed, a very compact SANS instrument was made. Current ones are 2.5 and 4m in total lengths. Many devices have to be developed, such as high intensity monochromator, beam branching device, high quality focusing mirror, and detector with high-resolution high-count-rate /highdetecting efficiency. Also important is to develop easy to use software.

The instrument was installed not at horizontal plane, but tilted by 45 degrees toward ceiling from the horizontal line.

The LPSD was installed just in front of the zinc-sulfide scintillation detector as shown

Prof Dr Michihiro FuRUSAKA successfully obtained about 2.5 mm FWHM focused beam at the detector position using a 2 mm aperture at one of the two focal points of the focusing mirror. SANS data was obtained from standard samples, such as Ni powder of 20 nm in diameter and micro-separated block-copolymer DI33.

He highlighted the issues of SANS for low power reactors; which is the efficiency of conversing collimator and loosely focused beam. The possible solutions proposed are converging multi-holes collimator from a bigger sample, and utilizing loosely focused beam by focusing mirrors.

Futhermore, Prof Dr Michihiro Furusaka also explained about the situation of nuclear scattering and proton particle beam accelerators in Malaysia.The lecture was cut short due to time constraints,but it was a very informative and eye opening lecture about quantum beam technology and its role in nuclear engineering.

(ALL THE PICTURES ABOVE ARE CREDITED TO THE WORK OF PROF DR MICHIHIRO FURUSAKA)

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Thank you Nuclear Malaysia and Dr Nor Azlan for inviting such a prestigious speaker to Uniten..hopefully the next time it can be planned with more time given to the speaker to finish his entire presentations

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